Summary

Nuclear transcribed genes produce mRNA transcripts destined to travel from the site of transcription to the cytoplasm for protein translation. Certain transcripts can be further localized to specific cytoplasmic regions. We examined the life cycle of a transcribed β-actin mRNA throughout gene expression and localization, in a cell system that allows the in vivo detection of the gene locus, the transcribed mRNAs and the cytoplasmic β-actin protein that integrates into the actin cytoskeleton. Quantification showed that RNA polymerase II elongation progressed at a rate of 3.3 kb/minute and that transactivator binding to the promoter was transient (40 seconds), and demonstrated the unique spatial structure of the coding and non-coding regions of the integrated gene within the transcription site. The rates of gene induction were measured during interphase and after mitosis, demonstrating that daughter cells were not synchronized in respect to transcription initiation of the studied gene. Comparison of the spatial and temporal kinetics of nucleoplasmic and cytoplasmic mRNA transport showed that the β-actin-localization response initiates from the existing cytoplasmic mRNA pool and not from the newly synthesized transcripts arising after gene induction. It was also demonstrated that mechanisms of random movement were predominant in mediating the efficient translocation of mRNA in the eukaryotic cell.

Andreas Villunger and colleagues discuss the biology of the PIDDosome multiprotein complex and recent advances that link PIDDosome-dependent CASP2 activation to p53 activation in response to extra centrosomes.

Centrosomes and cilia are essential structures for many functions in development and disease. Sascha Werner, Ana Pimenta-Marques and Mónica Bettencourt-Dias review how their structure and functions are maintained.

Marian Blanca Ramírez from the CSIC in Spain has been studying the effects of LRRK2, a protein associated with Parkinson’s disease, on cell motility. A Travelling Fellowship from Journal of Cell Science allowed her to spend time in Prof Maddy Parson’s lab at King’s College London, learning new cell migration assays and analysing fibroblasts cultured from individuals with Parkinson’s. Read more on her story here.

Where could your research take you? The deadline to apply for the current round of Travelling Fellowships is 30 Nov 2017. Apply now!